Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.738
Filtrar
1.
PLoS Biol ; 18(12): e3000702, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33370276

RESUMO

Understanding species' roles in food webs requires an accurate assessment of their trophic niche. However, it is challenging to delineate potential trophic interactions across an ecosystem, and a paucity of empirical information often leads to inconsistent definitions of trophic guilds based on expert opinion, especially when applied to hyperdiverse ecosystems. Using coral reef fishes as a model group, we show that experts disagree on the assignment of broad trophic guilds for more than 20% of species, which hampers comparability across studies. Here, we propose a quantitative, unbiased, and reproducible approach to define trophic guilds and apply recent advances in machine learning to predict probabilities of pairwise trophic interactions with high accuracy. We synthesize data from community-wide gut content analyses of tropical coral reef fishes worldwide, resulting in diet information from 13,961 individuals belonging to 615 reef fish. We then use network analysis to identify 8 trophic guilds and Bayesian phylogenetic modeling to show that trophic guilds can be predicted based on phylogeny and maximum body size. Finally, we use machine learning to test whether pairwise trophic interactions can be predicted with accuracy. Our models achieved a misclassification error of less than 5%, indicating that our approach results in a quantitative and reproducible trophic categorization scheme, as well as high-resolution probabilities of trophic interactions. By applying our framework to the most diverse vertebrate consumer group, we show that it can be applied to other organismal groups to advance reproducibility in trait-based ecology. Our work thus provides a viable approach to account for the complexity of predator-prey interactions in highly diverse ecosystems.


Assuntos
Peixes/microbiologia , Cadeia Alimentar , Microbioma Gastrointestinal/fisiologia , Animais , Teorema de Bayes , Tamanho Corporal , Recifes de Corais , Dieta , Ecologia , Ecossistema , Peixes/metabolismo , Modelos Teóricos , Filogenia , Reprodutibilidade dos Testes
2.
Int J Food Microbiol ; 334: 108815, 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-32966918

RESUMO

Histamine or scombrotoxin fish poisoning is caused by ingestion of bacterially produced histamine in fish. Histamine-producing bacteria generally contain the histidine decarboxylase gene (hdc). However, some strains of Photobacterium phosphoreum are known to produce significant levels of histamine, although the hdc gene in these strains has not been recognized. The objective of this study was to investigate a previously unidentified mechanism of histamine production by P. phosphoreum. We identified a protein with histidine decarboxylase (HDC) activity comparable to activity of the pyridoxal-5-phosphate (PLP) dependent HDC from P. kishitanii and M. morganii. The newly identified protein (HDC2) in P. phosphoreum and P. kishitanii strains, was approximately 2× longer than the HDC protein from other Gram-negative bacteria and had 12% similarity to previously identified HDCs. In addition, the hdc2 gene cluster in P. phosphoreum was identical to the hdc gene cluster in P. kishitanii. HDC2 had optimal activity at 20-35 °C, at pH 4, and was not affected by 0-8% NaCl concentrations. Compared to the hdc gene from P. kishitanii, expression of the hdc2 gene was constitutive and not affected by pH or excess histidine. This newly identified protein explains possible mechanisms of histamine production in P. phosphoreum. Characterization of this protein will help in designing control measures to prevent or reduce histamine production in fish.


Assuntos
Proteínas de Bactérias/metabolismo , Histidina Descarboxilase/metabolismo , Photobacterium/enzimologia , Animais , Proteínas de Bactérias/genética , Peixes/metabolismo , Peixes/microbiologia , Doenças Transmitidas por Alimentos/microbiologia , Histamina/biossíntese , Histidina Descarboxilase/genética , Concentração de Íons de Hidrogênio , Família Multigênica , Photobacterium/genética , Photobacterium/metabolismo , Fosfato de Piridoxal/metabolismo , Temperatura
3.
PLoS Negl Trop Dis ; 14(8): e0008406, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32776919

RESUMO

We hypothesized that Cholera (Vibrio cholerae) that appeared along Lake Kivu in the African Rift in the seventies, might be controlled by volcano-tectonic activity, which, by increasing surface water and groundwater salinity and temperature, may partly rule the water characteristics of Lake Kivu and promote V. cholerae proliferation. Volcanic activity (assessed weekly by the SO2 flux of Nyiragongo volcano plume over the 2007-2012 period) is highly positively correlated with the water conductivity, salinity and temperature of the Kivu lake. Over the 2007-2012 period, these three parameters were highly positively correlated with the temporal dynamics of cholera cases in the Katana health zone that border the lake. Meteorological variables (air temperature and rainfall), and the other water characteristics (namely pH and dissolved oxygen concentration in lake water) were unrelated to cholera dynamics over the same period. Over the 2016-2018 period, we sampled weekly lake water salinity and conductivity, and twice a month vibrio occurrence in lake water and fish. The abundance of V. cholerae in the lake was positively correlated with lake salinity, temperature, and the number of cholera cases in the population of the Katana health zone. V. cholerae abundance in fishes was positively correlated with V. cholerae abundance in lake water, suggesting that their consumption directly contaminate humans. The activity of the volcano, by controlling the physico-chemical characteristics of Lake Kivu, is therefore a major determinant of the presence of the bacillus in the lake. SO2 fluxes in the volcano plume can be used as a tool to predict epidemic risks.


Assuntos
Cólera/epidemiologia , Lagos/química , Lagos/microbiologia , Erupções Vulcânicas/efeitos adversos , Animais , República Democrática do Congo/epidemiologia , Condutividade Elétrica , Peixes/microbiologia , Humanos , Concentração de Íons de Hidrogênio , Oxigênio/análise , Ruanda , Salinidade , Dióxido de Enxofre/análise , Temperatura , Vibrio , Microbiologia da Água
4.
Lett Appl Microbiol ; 71(4): 359-368, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32713031

RESUMO

Staphylococci from Sheedal of Northeast India was isolated, identified and characterized. All the isolated staphylococci were found to be coagulase negative. Based on the rpoB gene sequences followed by analysis using NCBI-BLAST software, seven species of Staphylococcus namely, S. piscifermentans, S. condimenti, S. arlettae, S. sciuri, S. warneri, S. nepalensis and S. hominis were recognized. Phylogenetic analyses revealed three major cluster groups. All the seven Staphylococcus showed their NaCl tolerance from 2 to 8%. No species was able to grow at 55°C. Except S. arlettae and S. sciuri, all the isolated staphylococcal species exhibited growth at pH 4-8. No isolated species was able to ferment mannitol, sucrose and arabinose. All the species exhibited moderate to maximum proteolytic and lipolytic activities. All the seven species were found to be sensitive to the antibiotics, namely, erythromycin, norfloxacin, ampicillin, streptomycin and vancomycin, whereas all were resistant to co-trimoxazole. Only S. piscifermentans was found antagonist to Salmonella enterica, Escherichia coli and Bacillus subtilis, although the clear zone was minimal. All the staphylococcal species except S. arlettae and S. sciuri exhibited hydrophobicity ranging from 25 to 66%. The observed characteristics of isolated Staphylococci from Sheedal revealed their role in fish fermentation.


Assuntos
Alimentos e Bebidas Fermentados/microbiologia , Produtos Pesqueiros/microbiologia , Staphylococcus/isolamento & purificação , Ampicilina/farmacologia , Animais , Antibacterianos/farmacologia , Eritromicina/farmacologia , Fermentação , Peixes/microbiologia , Contaminação de Alimentos/análise , Índia , Filogenia , Staphylococcus/classificação , Staphylococcus/efeitos dos fármacos , Staphylococcus/genética
5.
Int J Food Microbiol ; 331: 108732, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32521374

RESUMO

The present study aimed to evaluate the anti-quorum sensing (anti-QS) and anti-proteolytic potentials of tarragon essential oil (TEO) and its major compounds against food-associated Pseudomonas spp. The activities were verified by in vitro, in silico and in situ approaches. In this work, methyl eugenol (ME)- and ß-phellandrene (ß-PH)-rich TEO was investigated. TEO at subMIC increased the percentage of saturated fatty acids in the bacterial membranes (from 7 to 22%) and exhibited anti-quorum sensing via decreasing the efficiency of QS autoinducer synthesis [3-oxo-C12-HSL (from 2.028 µg/mL to

Assuntos
Artemisia/química , Óleos Voláteis/farmacologia , Proteólise/efeitos dos fármacos , Pseudomonas/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , 4-Butirolactona/análogos & derivados , 4-Butirolactona/isolamento & purificação , 4-Butirolactona/farmacologia , Animais , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Simulação por Computador , Peixes/microbiologia , Homosserina/análogos & derivados , Homosserina/isolamento & purificação , Homosserina/farmacologia , Óleos Voláteis/química , Óleos Voláteis/isolamento & purificação , Pseudomonas/isolamento & purificação
6.
Int J Food Microbiol ; 328: 108664, 2020 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-32474229

RESUMO

To control Pseudomonas and Shewanella as important psychrotrophic spoilage bacteria in fish meat, we used ethanolic extracts of oregano (Origanum vulgare subsp. vulgare) and nettle (Urtica dioica), with phytochemical characterisation of the extracts and their bioactive compounds. Liquid chromatography coupled with photodiode array detection and electrospray ionisation-mass spectrometry was used for qualitative compositional determination of the extracts. Four main compounds were identified in the oregano extract, with rosmarinic acid the most abundant, followed by three glycosylated phenolics, one of which is reported for the first time in O. vulgare: 4'-O-ß-d-glucopyranosyl-3',4'-dihydroxybenzyl-4-hydroxybenzoate. Six main compounds were identified in the nettle extract, as caffeoylmalic acid and five flavonoid glycosides. These oregano and nettle ethanolic extracts showed in-vitro antimicrobial activities against selected Pseudomonas and Shewanella strains in broth and fish meat homogenate when evaluated at two inoculum concentrations. The antimicrobial activities were more pronounced for the nettle extract at the lower inoculum concentration, and for both the Shewanella strains. Growth inhibition in the fish meat homogenate was evaluated at 3.13 mg/mL and 1.56 mg/mL at 5 °C. Again, the nettle extract showed greater antimicrobial activity, which was seen as the lowest maximum growth rate, followed by the oregano extract, which was inhibitory only at 3.13 mg/mL. Finally, the extracts were applied to fish meat that was then stored at 5 °C for 9 days. Evaluation here was for the counts of the mesophilic, psychrotrophic, Pseudomonas and H2S producers. These confirmed the better antimicrobial effects of the nettle extract, especially against the H2S-producing bacteria, which included Shewanella. Both of the extracts were rich in glycosides of flavonoids and phenolic acids. The enzymatic activities of the Pseudomonas and Shewanella spoilage bacteria and their actions on the phenolic glycosides from natural sources will be further investigated.


Assuntos
Doenças dos Peixes/tratamento farmacológico , Origanum/química , Extratos Vegetais/farmacologia , Pseudomonas/efeitos dos fármacos , Shewanella/efeitos dos fármacos , Urtica dioica/química , Animais , Ácidos Cafeicos/farmacologia , Cinamatos/farmacologia , Depsídeos/farmacologia , Peixes/microbiologia , Flavonoides , Microbiologia de Alimentos , Hidroxibenzoatos/farmacologia , Malatos/farmacologia , Fenóis/química , Alimentos Marinhos/microbiologia , Espectrometria de Massas por Ionização por Electrospray
7.
Proc Biol Sci ; 287(1926): 20200184, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32372688

RESUMO

As the most diverse vertebrate group and a major component of a growing global aquaculture industry, teleosts continue to attract significant scientific attention. The growth in global aquaculture, driven by declines in wild stocks, has provided additional empirical demand, and thus opportunities, to explore teleost diversity. Among key developments is the recent growth in microbiome exploration, facilitated by advances in high-throughput sequencing technologies. Here, we consider studies on teleost gut microbiomes in the context of sustainable aquaculture, which we have discussed in four themes: diet, immunity, artificial selection and closed-loop systems. We demonstrate the influence aquaculture has had on gut microbiome research, while also providing a road map for the main deterministic forces that influence the gut microbiome, with topical applications to aquaculture. Functional significance is considered within an aquaculture context with reference to impacts on nutrition and immunity. Finally, we identify key knowledge gaps, both methodological and conceptual, and propose promising applications of gut microbiome manipulation to aquaculture, and future priorities in microbiome research. These include insect-based feeds, vaccination, mechanism of pro- and prebiotics, artificial selection on the hologenome, in-water bacteriophages in recirculating aquaculture systems (RAS), physiochemical properties of water and dysbiosis as a biomarker.


Assuntos
Aquicultura , Peixes/microbiologia , Microbioma Gastrointestinal , Ração Animal , Animais , Desenvolvimento Sustentável
8.
Sci Rep ; 10(1): 7839, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32398712

RESUMO

Experiments are reported to reconstruct the taphonomic pathways of fish toward fossilisation. Acrylic glass autoclaves were designed that allow experiments to be carried out at elevated pressure up to 11 bar, corresponding to water depths of 110 m. Parameters controlled or monitored during decay reactions are pressure, salinity, proton activities (pH), electrochemical potentials (Eh), and bacterial populations. The most effective environmental parameters to delay or prevent putrefaction before a fish carcass is embedded in sediment are (1) a hydrostatic pressure in the water column high enough that a fish carcass may sink to the bottom sediment, (2) hypersaline conditions well above seawater salinity, and (3) a high pH to suppress the reproduction rate of bacteria. Anoxia, commonly assumed to be the key parameter for excellent preservation, is important in keeping the bottom sediment clear of scavengers but it does not seem to slow down or prevent putrefaction. We apply our results to the world-famous Konservat-Lagerstätten Eichstätt-Solnhofen, Green River, and Messel where fish are prominent fossils, and reconstruct from the sedimentary records the environmental conditions that may have promoted preservation. For Eichstätt-Solnhofen an essential factor may have been hypersaline conditions. Waters of the Green River lakes were at times highly alkaline and hypersaline because the lake stratigraphy includes horizons rich in sodium carbonate and halite. In the Messel lake sediments some fossiliferous horizons are rich in FeCO3 siderite, a mineral indicating highly reduced conditions and a high pH.


Assuntos
Peixes , Fósseis , Pressão , Salinidade , Animais , Bactérias , Eletroquímica , Peixes/microbiologia , Concentração de Íons de Hidrogênio
9.
Int J Food Microbiol ; 325: 108626, 2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32325345

RESUMO

AIMS: The aim of this study was to evaluate the performance of sampling methods [contact plates, sponges, and swabs] in the recovery of biofilm Listeria monocytogenes populations considering the seafood environment conditions (nature of conditioning, of materials and bacterial species). METHODS AND RESULTS: Different materials (stainless steel, polyvinyl chloride, polyurethane) were conditioned with two fish filtrates, the ready-to-eat the most consumed in Europe (smoked salmon, cod). After, we added the suspension of Listeria monocytogenes, alone or with Pseudomonas fluorescens or Carnobacterium strains, and incubated for 48 h at 8 °C. Then, the 48 h-biofilms were sampled with different methods (contact plates, sponges, and swabs). The cultivable bacterial populations were enumerated on agar, while the L. monocytogenes total and viable populations were quantified by qPCR and propidium monoazide-qPCR (PMA-qPCR), respectively. The amount of L. monocytogenes in biofilms was affected only by the nature of the conditioning with lowest adherent bacteria with cod versus with smoked salmon conditioning. Considering the amount of total population, the swab displayed the lowest values versus the sponges and the contact plates. An explanation was that the observations of the swab by microscopy showed the bacteria trapped within it. The recovery of cultivable bacterial populations was not significantly different with the three sampling methods. On the contrary, we showed that the VBNC populations were only detached by two of three methods (contact plates, sponges) while for the dead populations, those were contact plates and swabs. CONCLUSIONS: The nature of the conditioning influenced the amount of the bacteria in biofilms. And the performance of the recovery of the bacterial populations (dead, VBNC, cultivable) was dependent on the methods used. SIGNIFICANCE AND IMPACT OF THE STUDY: This study showed that the seafood environmental conditions influenced the biofilm formation and the assessment of the efficiency of cleaning and disinfectant operations could be significantly affected by the used sampling methods.


Assuntos
Biofilmes/crescimento & desenvolvimento , Microbiologia de Alimentos/métodos , Listeria monocytogenes/isolamento & purificação , Alimentos Marinhos/microbiologia , Ágar , Animais , Azidas/química , Carnobacterium/isolamento & purificação , Desinfetantes/farmacologia , Europa (Continente) , Peixes/microbiologia , Propídio/análogos & derivados , Propídio/química , Pseudomonas fluorescens/isolamento & purificação , Aço Inoxidável/análise
10.
Food Microbiol ; 90: 103494, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32336371

RESUMO

P. psychrophila is implicated in fish spoilage especially under cold storage. In the present study, tandem mass tag (TMT) quantitative proteomic analysis was performed to clarify the molecular mechanism for the inhibitory effect of chitosan oligosaccharides (COS) against P. psychrophila in fish juice system. The MIC and MBC of the COS against P. psychrophila were 6 and 8 mg/mL, respectively. Compared with the untreated control, a total of 370 proteins (163 up-regulated and 207 down-regulated) were identified as differentially expressed proteins (DEPs, >1.5-fold or < 0.67-fold, P < 0.05) in P. psychrophila when exposed to 6 mg/mL COS. Bioinformatics analysis indicated that the DEPs were mainly involved in the cell wall/membrane, cell motility, and electron-transport chain; DNA replication, RNA transcription and translation, posttranslational modifications of proteins; TCA cycle, and the transport and metabolism of amino acid, carbohydrate, and ion. The scanning electron microscope (SEM) and fourier-transform infrared spectroscopy (FT-IR) analysis further validated that cell structure especially the cell wall/membrane was damaged after COS treatment. The results in this study presented an important step toward understanding the response of P. psychrophila cells to COS at the proteome level.


Assuntos
Quitosana/farmacologia , Peixes/microbiologia , Oligossacarídeos/farmacologia , Proteômica/métodos , Pseudomonas/genética , Animais , Membrana Celular/efeitos dos fármacos , Replicação do DNA/efeitos dos fármacos , Oligossacarídeos/química , Biossíntese de Proteínas/efeitos dos fármacos , Pseudomonas/química , Pseudomonas/efeitos dos fármacos , Transcrição Genética/efeitos dos fármacos
11.
Lett Appl Microbiol ; 71(1): 26-38, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32248555

RESUMO

One of the major problems to be addressed in aquaculture is the prominence of antimicrobial resistance (AMR). The occurrence of bacterial infections in cultured fishes promotes the continuous use of antibiotics in aquaculture, which results in the selection of proliferated antibiotic-resistant bacteria and increases the possibility of transfer to the whole environment through horizontal gene transfer. Hence, the accurate cultivation-dependent and cultivation-independent detection methods are very much crucial for the immediate and proper management of this menace. Antimicrobial resistance determinants carrying mobile genetic transfer elements such as transposons, plasmids, integrons and gene cassettes need to be specifically analysed through molecular detection techniques. The susceptibility of microbes to antibiotics should be tested at regular intervals along with various biochemical assays and conjugation studies so as to determine the extent of spread of AMR. Advanced omic-based and bioinformatic tools can also be incorporated for understanding of genetic diversity. The present review focuses on different detection methods to unearth the complexity of AMR in aquaculture. This monitoring helps the authorities to curb the use of antibiotics, commencement of appropriate management measures and adequate substitute strategies in aquaculture. The long battle of AMR could be overcome by the sincere implementation of One Health approach. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of antibiotics and increased antimicrobial resistance (AMR) are of major concerns in aquaculture industry. This could result in global health risks through direct consumption of cultured fishes and dissemination of AMR to natural environment through horizontal gene transfer. Hence, timely detection of the antimicrobial-resistant pathogens and continuous monitoring programmes are inevitable. Advanced microbiological, molecular biological and omic-based tools can unravel the menace to a great extent. This will help the authorities to curb the use of antibiotics and implement appropriate management measures to overcome the threat.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana/genética , Doenças dos Peixes/microbiologia , Peixes/microbiologia , Animais , Aquicultura , Bactérias/genética , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/veterinária , Transferência Genética Horizontal , Integrons/genética , Plasmídeos/genética , Uso Excessivo de Medicamentos Prescritos
12.
J Appl Microbiol ; 129(1): 116-136, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32141152

RESUMO

Probiotics administration in aquafeed is known to increase feed consumption and absorption due to their capacity to release a wide range of digestive enzymes and nutrients which can participate in digestion process and feed utilization, along with the absorption of diet components led to an increase in host's health and well-being. Furthermore, probiotics improve gut maturation, prevention of intestinal disorders, predigestion of antinutrient factors found in the feed ingredients, gut microbiota, disease resistance against pathogens and metabolism. The beneficial immune effects of probiotics are well established in finfish. However, in comparison, similar studies are less abundant in the shellfish. In this review, the discussions will mainly focus on studies reported the last 2 years. In recent studies, native probiotic bacteria were isolated and fed back to their hosts. Although beneficial effects were demonstrated, some studies showed adverse effects when treated with a high concentration. This adverse effect may be due to the imbalance of the gut microbiota caused by the replenished commensal probiotics. Probiotics revealed greatest effect on the shrimp digestive system particularly in the larval and early post-larval stages, and stimulate the production of endogenous enzymes in shrimp and contribute with improved the enzyme activities in the gut, as well as disease resistance.


Assuntos
Aquicultura , Bacillus/fisiologia , Suplementos Nutricionais , Lactobacillales/fisiologia , Probióticos/administração & dosagem , Fenômenos Fisiológicos da Nutrição Animal , Animais , Peixes/imunologia , Peixes/microbiologia , Microbioma Gastrointestinal , Probióticos/efeitos adversos , Frutos do Mar/microbiologia
13.
Appl Environ Microbiol ; 86(10)2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-32169941

RESUMO

Gastrointestinal (GI) or gut microbiotas play essential roles in host development and physiology. These roles are influenced partly by the microbial community composition. During early developmental stages, the ecological processes underlying the assembly and successional changes in host GI community composition are influenced by numerous factors, including dispersal from the surrounding environment, age-dependent changes in the gut environment, and changes in dietary regimes. However, the relative importance of these factors to the gut microbiota is not well understood. We examined the effects of environmental (diet and water sources) and host early ontogenetic development on the diversity of and the compositional changes in the gut microbiota of a primitive teleost fish, the lake sturgeon (Acipenser fulvescens), based on massively parallel sequencing of the 16S rRNA gene. Fish larvae were raised in environments that differed in water source (stream versus filtered groundwater) and diet (supplemented versus nonsupplemented Artemia fish). We quantified the gut microbial community structure at three stages (prefeeding and 1 and 2 weeks after exogenous feeding began). The diversity declined and the community composition differed significantly among stages; however, only modest differences associated with dietary or water source treatments were documented. Many taxa present in the gut were over- or underrepresented relative to neutral expectations in each sampling period. The findings indicate dynamic relationships between the gut microbiota composition and host gastrointestinal physiology, with comparatively smaller influences being associated with the rearing environments. Neutral models of community assembly could not be rejected, but selectivity associated with microbe-host GI tract interactions through early ontogenetic stages was evident. The results have implications for sturgeon conservation and aquaculture production specifically and applications of microbe-based management in teleost fish generally.IMPORTANCE We quantified the effects of environment (diet and water sources) and host early ontogenetic development on the diversity of and compositional changes in gut microbial communities based on massively parallel sequencing of the 16S rRNA genes from the GI tracts of larval lake sturgeon (Acipenser fulvescens). The gut microbial community diversity declined and the community composition differed significantly among ontogenetic stages; however, only modest differences associated with dietary or water source treatments were documented. Selectivity associated with microbe-host GI tract interactions through early ontogenetic stages was evident. The results have implications for lake sturgeon and early larval ecology and survival in their natural habitat and for conservation and aquaculture production specifically, as well as applications of microbe-based management in teleost fish generally.


Assuntos
Peixes/microbiologia , Microbioma Gastrointestinal , Trato Gastrointestinal/microbiologia , Animais , Dieta/veterinária , Peixes/crescimento & desenvolvimento , Sequenciamento de Nucleotídeos em Larga Escala/veterinária , RNA Bacteriano/análise , RNA Ribossômico 16S/análise , Qualidade da Água
14.
Int J Syst Evol Microbiol ; 70(3): 2034-2048, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32160147

RESUMO

Francisella noatunensis is a fastidious facultative intracellular bacterial pathogen that causes 'piscine francisellosis', a serious disease affecting both marine and fresh water farmed and wild fish worldwide. Currently two F. noatunensis subspecies are recognized, i.e. F. noatunensis subsp. noatunensis and F. noatunensis subsp. orientalis. In the present study, the taxonomy of F. noatunensis was revisited using a polyphasic approach, including whole genome derived parameters such as digital DNA-DNA hybridization, whole genome average nucleotide identity (wg-ANIm), whole genome phylogenetic analysis, whole genome G+C content, metabolic fingerprinting and chemotaxonomic analyses. The results indicated that isolates belonging to F. noatunensis subsp. orientalis represent a phenotypically and genetically homogenous taxon, clearly distinguishable from F. noatunensis subsp. noatunensis that fulfils requirements for separate species status. We propose, therefore, elevation of F. noatunensis subsp. orientalis to the species rank as Francisella orientalis sp. nov. with the type strain remaining as Ehime-1T (DSM 21254T=LMG 24544T). Furthermore, we identified sufficient phenotypic and genetic differences between F. noatunensis subsp. noatunensis recovered from diseased farmed Atlantic salmon in Chile and those isolated from wild and farmed Atlantic cod in Northern Europe to warrant proposal of the Chilean as a novel F. noatunensis subspecies, i.e. Francisella noatunensis subsp. chilensis subsp. nov. with strain PQ1106T (CECT 9798T=NCTC14375T) as the type strain. Finally, we emend the description of F. noatunensis by including further metabolic information and the description of atypical strains.


Assuntos
Francisella/classificação , Filogenia , Animais , Técnicas de Tipagem Bacteriana , Chile , DNA Bacteriano/genética , Europa (Continente) , Doenças dos Peixes/microbiologia , Peixes/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
15.
Trends Parasitol ; 36(3): 239-249, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32037136

RESUMO

In marine ecosystems, oceanographic processes often govern host contacts with infectious agents. Consequently, many approaches developed to quantify pathogen dispersal in terrestrial ecosystems have limited use in the marine context. Recent applications in marine disease modeling demonstrate that physical oceanographic models coupled with biological models of infectious agents can characterize dispersal networks of pathogens in marine ecosystems. Biophysical modeling has been used over the past two decades to model larval dispersion but has only recently been utilized in marine epidemiology. In this review, we describe how biophysical models function and how they can be used to measure connectivity of infectious agents between sites, test hypotheses regarding pathogen dispersal, and quantify patterns of pathogen spread, focusing on fish and shellfish pathogens.


Assuntos
Organismos Aquáticos , Métodos Epidemiológicos , Doenças dos Peixes/epidemiologia , Peixes , Modelos Biológicos , Frutos do Mar , Animais , Organismos Aquáticos/microbiologia , Organismos Aquáticos/parasitologia , Organismos Aquáticos/virologia , Ecossistema , Peixes/microbiologia , Peixes/parasitologia , Peixes/virologia , Frutos do Mar/microbiologia , Frutos do Mar/parasitologia , Frutos do Mar/virologia
16.
Microbiome ; 8(1): 9, 2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-32005134

RESUMO

BACKGROUND: Fish skin microbiomes are rarely studied in inland water systems, in spite of their importance for fish health and ecology. This is mainly because fish species distribution often covaries with other biotic and abiotic factors, complicating the study design. We tackled this issue in the northern part of the Jordan River system, in which a few fish species geographically overlap, across steep gradients of water temperature and salinity. RESULTS: Using 16S rRNA metabarcoding, we studied the water properties that shape the skin bacterial communities, and their interaction with fish taxonomy. To better characterise the indigenous skin community, we excluded bacteria that were equally abundant in the skin samples and in the water samples, from our analysis of the skin samples. With this in mind, we found alpha diversity of the skin communities to be stable across sites, but higher in benthic loaches, compared to other fish. Beta diversity was found to be different among sites and to weakly covary with the dissolved oxygen, when treated skin communities were considered. In contrast, water temperature and conductivity were strong factors explaining beta diversity in the untreated skin communities. Beta diversity differences between co-occurring fish species emerged only for the treated skin communities. Metagenomics predictions highlighted the microbiome functional implications of excluding the water community contamination from the fish skin communities. Finally, we found that human-induced eutrophication promotes dysbiosis of the fish skin community, with signatures relating to fish health. CONCLUSIONS: Consideration of the background water microbiome when studying fish skin microbiomes, across varying fish species and water properties, exposes patterns otherwise undetected and highlight among-fish-species differences. We suggest that sporadic nutrient pollution events, otherwise undetected, drive fish skin communities to dysbiosis. This finding is in line with a recent study, showing that biofilms capture sporadic pollution events, undetectable by interspersed water monitoring. Video abstract.


Assuntos
Bactérias/classificação , Peixes/microbiologia , Microbiota , Pele/microbiologia , Animais , Bactérias/metabolismo , Código de Barras de DNA Taxonômico , Disbiose , Poluição Ambiental/análise , Água Doce/microbiologia , Variação Genética , Metagenômica , RNA Ribossômico 16S/genética , Salinidade , Temperatura
17.
Int J Syst Evol Microbiol ; 70(4): 2305-2311, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32038006

RESUMO

A novel Gram-negative, obligately aerobic, rod-shaped and non-motile bacterium, designated strain K13M18T, was isolated from the intestinal tract of a Korean indigenous fish, oily bitterling (Acheilognathus koreensis). Strain K13M18T formed creamy-pink colonies on a marine agar plate. Results of phylogenetic analysis based on the 16S rRNA gene sequence similarity indicated that strain K13M18T was most closely related to Tabrizicola sediminis DRYC-M-16T, sharing 97.62 % similarity with that strain. Strain K13M18T belonged to the genus Tabrizicola, which formed a cluster with Tabrizicola aquatica RCRI19T, Tabrizicola fusiformis SY72T, Tabrizicola sediminis DRYC-M-16T and Tabrizicola alkalilacus DJCT in a phylogenetic tree based on the 16S rRNA gene sequences. Strain K13M18T grown optimally in 0 % (w/v) NaCl, at pH 7 and 30 °C, in a marine broth medium. The predominant cellular fatty acids were C18 : 1 ω7c and C18 : 1 ω6c. The major respiratory isoprenoid quinone was ubiquinone Q-10. Polar lipids of strain K13M18T contained phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, diphosphatidylglycerol, six unidentified aminophospholipids, one unidentified aminolipid and an unidentified lipid. Based on genome sequencing, the DNA G+C content of strain K13M18T was 64.08 mol %, with an average nucleotide identity value, calculated by a comparative genomic analysis of strains K13M18T and T. sediminis DRYC-M-16T, of 74.82 %. Based on the phylogenetic, genotypic, and phenotypic information, strain K13M18T is proposed to be a novel species of the genus Tabrizicola. The type strain is K13M18T (=KCTC 62659T=JCM 33230T).


Assuntos
Peixes/microbiologia , Trato Gastrointestinal/microbiologia , Filogenia , Rhodobacteraceae/classificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Água Doce , Fosfolipídeos/química , Pigmentação , RNA Ribossômico 16S/genética , República da Coreia , Rhodobacteraceae/isolamento & purificação , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
18.
Sci Rep ; 10(1): 2895, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-32076035

RESUMO

Caligus rogercresseyi is a copepod ectoparasite with a high prevalence in salmon farms in Chile, causing severe welfare and economic concerns to the sector. Information on the parasite's underpinning mechanisms to support its life strategy is recently being investigated. Due to the critical role of microbiota, this study aimed to characterize the microbiota community associated with C. rogercresseyi from different regions with salmon aquaculture in Chile. Using third-generation sequencing with Nanopore technology (MinION) the full 16S rRNA gene from sea lice obtained from 8 areas distributed over the three main aquaculture regions were sequenced. Microbiota of the parasite is mainly comprised of members of phyla Proteobacteria and Bacteroidetes, and a core microbiota community with 147 taxonomical features was identified, and it was present in sea lice from the three regions. This community accounted for 19% of total identified taxa but more than 70% of the total taxonomical abundance, indicating a strong presence in the parasite. Several taxa with bioactive compound secretory capacity were identified, such as members of genus Pseudoalteromonas and Dokdonia, suggesting a possible role of the lice microbiota during the host infestation processes. Furthermore, the microbiota community was differentially associated with the salmon production, where several potential pathogens such as Vibrio, Tenacibaculum, and Aeromonas in Los Lagos, Aysén, and Magallanes region were identified. Notably, the Chilean salmon industry was initially established in the Los Lagos region but it's currently moving to the south, where different oceanographic conditions coexist with lice populations. The results originated by this study will serve as foundation to investigate putative role of sea lice as vectors for fish pathogens and also as reservoirs for antibiotic-resistant genes.


Assuntos
Copépodes/microbiologia , Reservatórios de Doenças/microbiologia , Peixes/microbiologia , Peixes/parasitologia , Microbiota/genética , Sequenciamento por Nanoporos , Animais , Biodiversidade , Chile , Análise por Conglomerados , Geografia , Filogenia
19.
Pak J Biol Sci ; 23(3): 278-286, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31944089

RESUMO

BACKGROUND AND OBJECTIVE: Recently, there has been evidence for the accumulation of steroid hormones in the water environment with negative consequences on fish and humans. However, there is paucity of information on how the steroid hormones influence the microbial community in environmental waters. The objective of this study was to determine the occurrence of 17ß-estradiol (E2) and its potential influence on the diversity of Aeromonas spp. MATERIALS AND METHODS: Wastewater samples were obtained from sewage treatment plants in northern South Africa and fish samples were collected from the Nandoni dam. Aeromonas spp. were isolated using microbiological methods and PCR protocols were used for their identification. A commercial Elisa kit was used for measuring the concentration of 17ß-estradiol (E2) from the wastewater samples as well as the fish samples. RESULTS: 17ß-estradiol (E2) was found in high concentration in sewage samples varying from 0.32-348.6 pg mL-1 while in fish samples, it ranged from 1.1-73.6 pg mL-1. There was a tendency of samples with high E2 concentrations to have higher diversity of Aeromonas spp., implying that steroid hormones may serve as nutrient for Aeromonas spp. Aeromonas hydrophila was the most prevalent species (71%), followed by A. sobria with (68%). CONCLUSION: The presence of Aeromonas spp. in environmental waters and fish that is consumed by the local community poses a serious health concern. The high content of E2 in treated wastewater is of serious concern as well. For the first time, the present study showed a positive impact of E2 on Aeromonas growth.


Assuntos
Aeromonas/isolamento & purificação , Estradiol/farmacologia , Peixes/microbiologia , Águas Residuárias/microbiologia , Microbiologia da Água , Aeromonas/classificação , Ágar/química , Animais , Ensaio de Imunoadsorção Enzimática , Estradiol/química , Técnicas Microbiológicas , Reação em Cadeia da Polimerase , África do Sul , Eliminação de Resíduos Líquidos , Purificação da Água , Abastecimento de Água
20.
Microb Ecol ; 80(1): 212-222, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31932881

RESUMO

Microorganisms are an important component in shaping the evolution of hosts and as such, the study of bacterial communities with molecular techniques is shedding light on the complexity of symbioses between bacteria and vertebrates. Teleost fish are a heterogeneous group that live in a wide variety of habitats, and thus a good model group to investigate symbiotic interactions and their influence on host biology and ecology. Here we describe the microbiota of thirteen teleostean species sharing the same environment in the Mediterranean Sea and compare bacterial communities among different species and body sites (external mucus, skin, gills, and intestine). Our results show that Proteobacteria is the dominant phylum present in fish and water. However, the prevalence of other bacterial taxa differs between fish and the surrounding water. Significant differences in bacterial diversity are observed among fish species and body sites, with higher diversity found in the external mucus. No effect of sampling time nor species individual was found. The identification of indicator bacterial taxa further supports that each body site harbors its own characteristic bacterial community. These results improve current knowledge and understanding of symbiotic relationships among bacteria and their fish hosts in the wild since the majority of previous studies focused on captive individuals.


Assuntos
Bactérias/isolamento & purificação , Fenômenos Fisiológicos Bacterianos , Peixes/microbiologia , Interações entre Hospedeiro e Microrganismos , Microbiota , Animais , Bactérias/classificação , França , Microbioma Gastrointestinal , Brânquias/microbiologia , Intestinos/microbiologia , Mar Mediterrâneo , Muco/microbiologia , Pele/microbiologia , Especificidade da Espécie
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...